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41.
42.
Quantum phase transitions occur when the ground state of a quantum system undergoes a qualitative change when an external control parameter reaches a critical value. Here, we demonstrate a technique for studying quantum systems undergoing a phase transition by coupling the system to a probe qubit. It uses directly the increased sensibility of the quantum system to perturbations when it is close to a critical point. Using an NMR quantum simulator, we demonstrate this measurement technique for two different types of quantum phase transitions in an Ising spin chain. 相似文献
43.
Morenzoni E Luetkens H Prokscha T Suter A Vongtragool S Galli F Hesselberth MB Garifianov N Khasanov R 《Physical review letters》2008,100(14):147205
We have performed depth dependent muon-spin-rotation and -relaxation studies of the dynamics of single layer films of AuFe and CuMn spin glasses as a function of thickness and of its behavior as a function of distance from the vacuum interface (5-70 nm). A significant reduction in the muon-spin relaxation rate as a function of temperature with respect to the bulk material is observed when the muons are stopped near (5-10 nm) the surface of the sample. A similar reduction is observed for the whole sample if the thickness is reduced to, e.g., 20 nm and less. This reflects an increased impurity spin dynamics (incomplete freezing) close to the surface although the freezing temperature is only modestly affected by the dimensional reduction. 相似文献
44.
Fast Exfoliation and Functionalisation of Two‐Dimensional Crystalline Carbon Nitride by Framework Charging 下载免费PDF全文
Dr. Jingjing Jia Dr. Edward R. White Dr. Adam J. Clancy Dr. Noelia Rubio Theo Suter Dr. Thomas S. Miller Kit McColl Prof. Paul F. McMillan Dr. Veronika Brázdová Prof. Furio Corà Dr. Christopher A. Howard Robert V. Law Dr. Cecilia Mattevi Prof. Milo S. P. Shaffer 《Angewandte Chemie (International ed. in English)》2018,57(39):12656-12660
Two‐dimensional (2D) layered graphitic carbon nitride (gCN) nanosheets offer intriguing electronic and chemical properties. However, the exfoliation and functionalisation of gCN for specific applications remain challenging. We report a scalable one‐pot reductive method to produce solutions of single‐ and few‐layer 2D gCN nanosheets with excellent stability in a high mass yield (35 %) from polytriazine imide. High‐resolution imaging confirmed the intact crystalline structure and identified an AB stacking for gCN layers. The charge allows deliberate organic functionalisation of dissolved gCN, providing a general route to adjust their properties. 相似文献
45.
We have demonstrated sensitive label-free virus detection using the opto-fluidic ring resonator (OFRR) sensor. The OFRR is a novel sensing platform that integrates the microfluidics and photonic sensing technology with a low detection limit and small volume. In our experiment, filamentous bacteriophage M13 was used as a safe model system. Virus samples were flowed through the OFRR whose surface was coated with M13-specific antibodies. We studied the sensor performance by monitoring in real-time the virus and antibody interaction. It is shown that OFRR can detect M13 with high specificity and sensitivity. The detection limit is approximately 2.3 x 10(3) pfu mL(-1) and the detection dynamic range spanned seven orders of magnitude. Theoretical analysis was also carried out to confirm the experimental results. Our study will lead to development of novel OFRR-based, sensitive, rapid, and low-cost micro total analysis devices for virus detection. 相似文献
46.
The photochemistry of CO(CN)2 in cryogenic matrixes has been investigated employing pulsed laser excitation at 193 nm. During irradiation, the parent molecule, the intermediate, and the final photoproducts were monitored by IR spectroscopy. Four new species were identified including the isocyano isomer of the parent NCC(O)NC, cyanogen NCCN, isocyanogen CNCN, and CO according to spectroscopic features and ab initio calculations. After prolonged irradiation, the only remaining species were CO and the two isomers NCCN and CNCN. A reaction scheme is proposed which is in agreement with the first dissociation step being a branching of the decay path into the radical channel to CN+OCCN and the molecular channel to CO+(CN)2. The caged radicals of the former reaction either recombine to the parent molecule and its isomer which are both photolyzed again or they react directly to the stable and final products. 相似文献
47.
Suter H.U. Hüsser P. Stoll E.P. Schafroth S. Meier P.F. 《Hyperfine Interactions》1999,120(1-8):137-140
Spin-polarized ab-initio cluster procedures are used to investigate the electronic structure of CuO2-planes in the La2CuO4 and YBa2Cu3O7 compounds. In particular, electric field gradients (EFGs) and magnetic hyperfine interaction parameters for the Cu sites
were calculated with various theoretical methods. Calculations with density functional theory reproduce the experimentally
determined EFGs fairly well while those at the Hartree-Fock level generally yield values which are too large by about 40%.
The anisotropic magnetic hyperfine coupling can also be calculated with reasonable accuracy.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
48.
Matthias Westerhausen Christin Birg Holger Piotrowski Tassilo Habereder Max Suter Heinrich Nth 《无机化学与普通化学杂志》2001,627(5):882-890
Formation of Alkaline Earth Metal‐Arsenic Cages via the Metalation of Triisopropylsilylarsane with Calcium, Strontium, and Barium Bis[bis(trimethylsilyl)amide] in Tetrahydrofuran The metalation of triisopropylsilylarsane with the alkaline earth metal bis[bis(trimethylsilyl)amides] in tetrahydrofuran yields the THF complexes of calcium ( 1 ), strontium ( 2 ), and barium‐bis(triisopropylsilylarsanide) ( 3 ). Dissolving of these compounds in toluene leads to the elimination of triisopropylsilylarsane and the formation of the THF complexes of tetraalkaline earth metal hexakis(triisopropylsilylarsanide)‐triisopropylsilylarsanediide of calcium ( 4 ), strontium ( 5 ), and barium ( 6 ), respectively. The central polyhedron of compound 4 can be described as two trigonal bipyramids with the metal atoms in apical positions, connected via the arsanediide substituent as a common corner. The central moieties of the compounds 5 and 6 consist of four trigonal bipyramids which are connected by common edges as well as common faces. 相似文献
49.
50.
B. Betev J. J. Blaising P. Bordalo A. Boumediene L. Cerrito A. Degré A. Ereditato S. Falciano K. Freudenreich E. Gorini M. Guanziroli H. Hofer P. Juillot L. Kluberg P. Lecomte P. Le Coultre R. Morand B. Mours A. Romana R. Salmeron P. Strolin H. Suter V. L. Telegdi J. Varela G. Viertel J. Wallace-Hadrill M. Winter NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,28(1):15-22